Estate agents or house buying experts.

[Ihopeyourcakeisshit]

Recently sold our house, looking to buy and currently in a rental. Our last and only house was bought off plan so we don't have much experience.
We had an offer rejected today as the vendor had received a better offer. We weren't asked if we wanted to consider upping ours, is this normal? Is the onus on us to increase our offer if we want or is it likely to be a done deal?

I think this falls into the age old "don't ask, don't get" category. Speak to the agents - say you want to increase your offer. I have a feeling, but might be wrong, that agents have a duty to inform the sellers of all offers received.